Looking to get some background on sheet metal fabrication?
According to Thomas Net:
“Sheet metal fabrication is an umbrella term for a group of processes that use sheet metal to build machines and structures. It can be a complex process involving many different professionals. Businesses that specialize in sheet metal fabrication are commonly referred to as fabrication shops, or fab shops for short. Although we’ve already covered types of metal fabrication on a broader level, this article will focus on the materials, processes, and tools related to sheet metal fabrication.
“Here’s what this guide will cover:
- “Types of Sheet Metal Fabrication Metals
- “Sheet Metal Fabrication Processes
- “Sheet Metal Fabrication Tools
- “Industries and Applications
Types of Sheet Metal Fabrication Metals
“Sheet metal can come in a wide variety of types, and fabrication can adapt the metal to whatever purposes you may need. Types of common metals used in sheet metal fabrication include:
- “Steel. There is a multitude of types of steels for all sorts of purposes, but the metal as a whole is known for its durability and strength.
- “Aluminum is more lightweight while also sharing some of steel’s strength. It’s good for lower temperatures, which partially accounts for its use in aerospace and refrigeration.
- “Magnesium is a structural metal with a very low density, excellent for when stiffness is needed.
- “Brass has useful acoustic properties, but is also used often for fittings and components. It is lightweight and corrosion-resistant.
- “Bronze has a low melting point and is stronger than copper, with applications in coins, cookware, and turbines.
- “Copper is ductile, malleable, and electrically conductive, as well as corrosion-resistant.
Sheet Metal Fabrication Processes
“There are three main types of sheet metal fabrication: forming, cutting, and joining. We’ll outline each one.
“Forming includes processes like stamping, bending, stretching, and roll forming. While cutting subtracts material from a piece of sheet metal, forming simply reshapes it to the desired contours.
- “Stamping, which is explained in more detail here, uses single or progressive dies to press the metal into the desired form. The technique uses two dies with a sheet of metal pressed between them.
- “Bending can be done either by press brakes or by hand.
- “Stretching, as is implied in the name, pulls metal apart via stretcher, hammer and dolly, or English wheel.
- “Roll forming has similar effects to bending. However in this process the entire sheet of metal passes through a pair of rolls to form the material into the right shape so it can be bent all along its length into a coil.
“There are two different types of cutting: with shear and without shear. Shear cutting includes processes such as shearing, cutting, and blanking. These types of cuts are more commonly used for nonindustrial end products, since they are less precise than processes without shear.
- “Basic cutting uses a single blade to cut through the material.
- “Blanking is a more powerful version of the same process a hole punch uses to cut out holes in paper. A machine punches shaped pieces out of a sheet of metal, and the leftover sheet is discarded.
- “Shearing involves the same type of action as scissors, using upper and lower blades that make cuts in straight lines. However, with shearing, one blade remains stationary while the other lowers down.
“Non-shear cutting, which is more accurate, is used specifically for industrial products like airplane wings. These processes include laser beam, plasma, and waterjet cutting services, as well as machining.
- “Laser cutting uses a focused beam of light for cutting through or engraving the material.
- “Plasma uses heated compressed gases like nitrogen and hydrogen, which exit the nozzle as such high speed they become ionized and conduct electricity.
- “Waterjet cutting shoots high speed, concentrated streams of water filled with abrasives to erode a cut into the material.
- “Machining uses a tool like a drill bit or lathe blade to cut off pieces of material. This can include processes like milling and spinning.
“Joining encompasses the processes of welding, brazing, riveting, and adhesive use.
- “Welding comes in several forms, including MIG, TIG, and stick. It acts by fusing the metal sheets together through melting them, while adding a filler.
- “Brazing is a similar process, but it acts by melting a filler without melting the sheets.
- “Riveting relies on small metal parts to join sheets of material by embedding them through both sheets.
- “Adhesives hold together metal sheets either alone, as in the case of structural adhesives, or in conjunction with another joining method, as with machinery adhesives.
“Once the metal has been fabricated there are finishing processes that can be performed to enhance its properties, including sandblasting, deburring, annealing, and coating.
Sheet Metal Fabrication Tools
“Sheet metal fabrication relies on a special set of tools across its cutting, forming, and joining processes to force the metal into the desired shape. Across multiple categories of tools, however, CNC (Computer Numerically Controlled) machines have become a popular tool. CNC machines are computers that are programmed to perform specific tasks and achieve the exact specifications required to manufacture many products. They have gained enormous popularity for their precision and reduction of labor costs. Their use has contributed to the increasing need for CAD files, which can be loaded into the computer to perform turning, bending, or welding.
“For the cutting processes, sheet metal fabrication uses band, miter, and chop saws, as well as cutting torches. Band saws have special hardened blades and a feed to ensure even cutting. Chop and miter saws are also used, which have an abrasive disk specifically made for cutting sheet metal (chop saws move up and down, while miter saws can cut at an angle). Cutting torches (which use flame and a stream of oxygen) are also used in sheet metal fabrication. They can cut large pieces of sheet metal without much effort.
“Sheet metal fabrication also involves the use of hydraulic breaks and rolling machines, as well as oxy-acetylene torches, in its forming processes. With breaks, sheet metal fabrication is simplified as they help create bends at predetermined angles. Rolling machines are also used in sheet metal fabrication to form steel into rolls, creating a more finished product in a shape like a roll of paper towels. Straightening warped steel during sheet metal fabrication is accomplished with an Oxy-acetylene torch. With straightening, heat is applied to the metal in a slow, linear fashion. Using this method, a highly skilled welder can remove even significant warpage.
“Joining sheet metal often involves welding. After the sheet metal parts are formed, they are assembled and tack welded into place. Various welding techniques can be used in sheet metal fabrication to avoid warping or other visual defects. These include using a stout fixture, welding in a staggered manner, covering the metal with sand during the cooling process, and special straightening processes. Other joining technology includes rivet guns and brazing equipment.
Industries and Applications for Sheet Metal Fabrication
“Sheet metal fabrication is a very flexible process, so it can be used in most industries to create everything from components to automotive bodies. Some industries that rely on it include the aerospace, construction, automotive, HVAC, consumer goods, robotics, electronics, and energy sectors, but that is far from an exhaustive list. That’s because the need for industrial products from metal is everywhere, from housings to gears to containers. Metal is a strong and lasting material used in every industry. A product made from sheet metal is generally easier or faster (and therefore less expensive) to make than a product made from casting or additive manufacturing.”